A simple ROI calculator that turns an investment cost and an expected benefit into a percentage return, with a plain account of what that percentage cannot see.
Enter the total cost of the investment and the benefit you expect it to produce. The calculation runs in your browser with simple arithmetic: nothing is stored, and no AI interprets your figures.
Last reviewed 3 July 2026 · Free and ungated
Put the business case to selected senior operators from the Global Board who have seen how these forecasts behave after approval.
Challenge the assumptions before committingROI = (benefit − cost) ÷ cost, shown as a percentage. How our tools work
ROI is the gain relative to what you put in: subtract the investment cost from the expected benefit, divide by the cost, and express the result as a percentage. A positive figure means the benefit exceeds the cost on paper; a negative figure means the investment destroys value even before risk is considered. The arithmetic is the easy part. The two inputs are where every serious argument happens.
Suppose a new order-management system costs €200,000 all-in and the business case claims €260,000 of benefit over the period you are measuring. The gain is €260,000 − €200,000 = €60,000. Divide by the €200,000 cost and you get 0.30, so the ROI is 30%. The same arithmetic at €190,000 of benefit gives −5%: a €70,000 swing in a benefit estimate, well within normal forecasting error, moves the case from approval to rejection.
An ROI figure looks precise, which is exactly why it deserves suspicion. Before anyone quotes this number in an approval paper, pressure-test what it assumes away.
This calculator does one division. It is not a substitute for a cash-flow model, a sensitivity analysis or a finance review, and it cannot tell you whether the benefit estimate was built up from evidence or backed into from a target. Its useful function is to make the claimed return explicit enough to argue about.
Only value you can trace to the investment: incremental revenue, avoided cost or reduced spend, measured over a stated period. If the benefit line includes gains that would have happened anyway, the ROI is inflated before the arithmetic starts.
There is no universal threshold. A 30% return with high confidence over one year is a different proposition from 30% claimed over five years on untested assumptions. Compare against your cost of capital and against the other uses of the same money.
Deliberately. It mirrors the simple ROI figure that appears in most board papers, so you can see what that figure does and does not contain. For multi-year decisions, ask finance for an NPV alongside it rather than trusting either number alone.